Force sensors measuring the deformation of a substrate using a path for an acoustic surface wave are known. When a force acts upon the substrate, the time needed by the acoustic surface wave to cover the path is changed.
The force sensor according to the present invention has the advantage over the related art that the effect of a force on the substrate can be detected in two directions perpendicular to one another. Thus different force components can be measured using a single sensor element.
A particularly simple embodiment of the path is represented by comb-shaped capacitor structures and barriers. A substrate made of a piezoelectric material is particularly easy to use here. The electric signals are advantageously transmitted and received via an antenna. The substrate is implemented in a particularly simple manner by a plate on whose top surface the first and second paths are implemented. Additional paths can be arranged on the bottom of the plate-shaped substrate in order to allow a force component to be measured in a third direction. The substrate can also be provided for embedding in an elastic material.